HUBBLE SPACE TELESCOPE
DAILY REPORT # 3128
PERIOD COVERED: 0000Z (UTC) 05/31/02 - 0000Z (UTC) 06/02/02
OBSERVATIONS SCHEDULED AND ACCOMPLISHED:
9353
Direct imaging of the progenitors of massive, core-collapse supernovae
Modern supernovae searches in the nearby Universe are discovering vast numbers
of SNe which have massive star progenitors {Types II, Ib and Ic}. The extensive
HST {and ground-based} image archives of galaxies within ~20 Mpc enables their
individual bright stellar content to be resolved. As massive, evolved stars are
the most luminous single objects in a galaxy, the progenitors of core-collapse
SNe should be directly detectable on pre-explosion images. Within the last year
we have set direct mass limits on the progenitors of two SNe Type II-P by
analyzing pre-explosion archive images and follow up HST exposures. We have now
identified six other recent, nearby SNe which have WFPC2 archive exposures of
the site taken before explosion. Additionally, our Cycle 10 SNAP program will
double the WFPC2 image archive of nearby galaxies which significantly increases
the chances of having multi-colour photometry of pre-explosion sites for future
SNe. In this Cycle, we request time on two fronts. Firstly we require
imaging of
the six SNe with existing pre-explosion data in order to perform exact
astrometry of the SNe positions to around 0.05''. Secondly, as a follow on from
our two successful Cycle 10 programs, we request ToO status for any nearby
core-collapse SN which explodes during Cycle 11 and which has pre-explosion HST
images. The goal of this proposal is to directly identify the progenitor stars
of core-collapse SNe.
ACS 9586
ACS Polarization Calibration
This proposal aims to calibrate the polarization modes most heavily used in
Cycle 11. We need L-flat observations, observations of a polarized star and an
unpolarized star, and an observation of an extended polarized source.
ACS 9476
Galaxy Evolution in the Richest Clusters at z=0.8: the EDisCS Cluster Sample
The study of distant cluster galaxies requires two key ingredients: {1} deep
high-resolution imaging, to constrain galaxy structure; and {2} 8m-class
spectroscopy, to measure stellar content, star-formation rates, dynamics, and
cluster membership. We will reach both conditions with the addition of HST/ACS
imaging to our suite of VLT {36 nights} and NTT {20 nights} observations of 10
confirmed clusters at z~0.8, drawn from the ESO Distant Cluster Survey
{EDisCS}.
The proposed HST/ACS data will complement our existing optical/IR imaging and
spectroscopy with quantitative measures of cluster galaxy morphologies {i.e.
sizes and shapes, bulge-disk decompositions, asymmetry parameters}, and with
measurements of cluster masses via weak lensing. Major advantages unique to the
EDisCS project include: {i} uniform selection of clusters; {ii} large enough
sample sizes to characterize the substantial cluster-to-cluster variation in
galaxy populations; {iii} large quantities of high quality data from 8m
telescopes; {iv} uniform measurements of morphologies, spectroscopic and
photometric redshifts, SEDs, star-formation/AGN activities, and internal
kinematics; {v} optical selection of clusters to complement the X-ray selection
of almost all high-z clusters in the ACS GTO programs; {vi} forefront numerical
simulations designed specifically to allow physical interpretation of observed
differences between the high-z and local clusters.
ACS 9024
SBC flat field uniformity
The stability and uniformity of the low-frequency flat fields {L-flat} of all
ACS detectors will be assessed by using multiple pointing observations of the
globular cluster NGC6681 - thus imaging moderately dense stellar fields. By
placing the same star over different portions of the detectors and measuring
relative changes in its brightness it will be possible to determine local
variations in the response of the detectors. Based on previous experience with
STIS, it is deemed that a total of nine different pointings will suffice to
provide adequate characterization of the flat field stability in any given
band.
For each filter to be tested, the baseline consists of 9 pointings with
steps of
~20% of the FOV in a diagonal cross pattern. During SMOV, the complement of
filters to be tested is limited to the following: for the SBC, F125LP and
F150LP. In order to provide complementary data for the geometric distortion
programmes {9027 and 9028}, and also to check that the distortion is not
chromatic, three additional exposures will be taken with F125LP with a very
small {~10 pixel} offset from the centre {see proposals 9027 and 9028}.
Execution of this programme must await completion of programme 9011 {ACS to FGS
alignment} and the ensuing PDB update.
ACS/CAL 9558
ACS weekly Test
This program consists of basic tests to monitor, the read noise, the
development
of hot pixels and test for any source of noise in ACS CCD detectors. This
programme will be executed once a day for the entire lifetime of ACS.
ACS/SBC 9022
SBC Dark Current Measurement
This proposal acquires dark count images for the ACS/SBC. As the dark rate is
expected to be a strong function of detector temperature, the sequence is
designed to fill an entire block of non-SAA orbits. Over that time, the
detector
temperature is expected to rise with time since turn on.
ACS/WFC 9584
ACS Default {Archival} Pure Parallel Program II.
The Advanced Camera for Surveys (WFC) was used to test ACS pure parallels.
ACS/WFC 9575
Default {Archival} Pure Parallel Program.
The Advanced Camera for Surveys (WFC) was used to test ACS pure parallels in
POMS.
ACS/WFC/HRC 8947
Weekly Test.
The Advanced Camera for Surveys (WFC and HRC) was used to perform basic
tests to
monitor, the read noise, the development of hot pixels and test for any source
of noise in ACS CCD detectors. This program will be executed at least once
a day
for the entire lifetime of ACS.
HST 9382
A Large Targeted Survey for z < 1.6 Damped Lyman Alpha Lines in SDSS QSO
MgII-FeII Systems.
We have searched the first public release of SDSS QSO spectra for low-z
{z<1.65}
metal absorption lines and found over 200 large rest equivalent width MgII-FeII
systems. Previously, we empirically showed that such systems are good
tracers of
large neutral gas columns, with ~50% being classical damped Lyman alpha {DLA}
systems {N_HI>=2*10^20 cm^-2}. Here we propose to follow up a well-defined
subset of 79 of them to search for DLAs with 0.47